My '14 Saga (head gasket or not)?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Shenine, Dec 21, 2021.

  1. Shenine

    Shenine New Member

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    Hello all, here is my story (I'll try to keep it as concise as possible):

    I own a '14 Prius, got it in June 2021 at 179k miles. To my knowledge from the previous owner, the spark plugs, ignition coils, and fuel injectors were not changed out nor was the EGR was not cleaned out.

    In early November, I took my car in to a local shop in the Atlanta area because I was getting the dreaded engine shakes upon cold startups. They diagnosed my problem as a bad head gasket based on these findings:
    • error codes P0300, P0301, P0302, P0304
    • engine shake on startup for 30 sec - 1 min
    • signs of wetness on the piston cylinders (see attached photos)
    I garaged my car for a couple weeks, and decided to get my car towed to my regular mechanic in Early December for further inspection (and his price range is more in my budget haha). He did a combustion test, which back normal and made him second guess the head gasket diagnosis from the previous shop. He also checked the spark plugs and saw that they were not looking great, so he replaced those along with the ignition coils. That seemed to have solved the problem, until now. The shakes have come back, a bit more viscously I would say since they started occurring when the engine cuts on during a drive as well.

    Could it truly be the head gasket? My regular mechanic mentioned when he pulled out the spark plugs, they smelled like gasoline and did not have signs of coolant on them before he replaced them. He also said he believes the wetness was caused by the plugs too. I'm just so worried, especially because the EGR hasn't been cleaned out and my mechanic seems to not think that may be necessary to do. @Mendel Leisk you seem like the expert in this area; any thoughts? Should my mechanic do a leak down test? And if anyone else has experience with these specific symptoms, I would greatly appreciate your input as well.
     

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    #1 Shenine, Dec 21, 2021
    Last edited: Dec 21, 2021
  2. Raytheeagle

    Raytheeagle Senior Member

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  3. 2010moneypit?

    2010moneypit? Junior Member

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    Could be a head gasket for sure.
     
  4. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Yes. Well, maybe another mechanic. Because of this:

    And this, very likely not necessary:

    Gen 3 with 179K, EGR and intake manifold never been cleaned, it's very, very likely head gasket failure. There are countless tales here, where everything else is suspected first, everything else tried first. Leak-down test is the best way to check the head gasket integrity, see if it's leaking, and where.

    I'd suspect the car was sold because of this condition; do you have any recourse, was it a dealership for example?

    See first link in my signature, has EGR info. There's also links for head gasket replacement info.

    The sand pounder: Toyota doesn't want to know about it... :mad:
     
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  5. The Critic

    The Critic Resident Critic

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    Leakdown test or pressure-pulse sensor should verify the HG failure:



    My opinion is that the HG and EGR issues are unrelated, but we can save that discussion for a different day. The coating just degrades on the HG. I've seen it on a few 2GR's too.
     
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  6. Shenine

    Shenine New Member

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    Hello all, I'm back with an update:

    I went to a new mechanic near my parent's house, and told them everything I described above. This time I also noticed on my way home from the city, my coolant went down. They agreed to run another combustion test, and if that is inconclusive, do a leak down. Sure enough, the liquid turned green on the combustion. They diagnosed it as a head gasket issue, which I knew it was all along! I'm just glad to finally get clear confirmation of my issue. Tomorrow they are sending the parts out to the machine shop. The mechanics thoughts were that the other shop's combustion test was faulty, and the other should have been able to tell me why it was a head gasket further than cylinder wetness.

    They also are going to clean my EGR system and any other parts looking gunky out while they are doing the repair, at my request. If y'all have recommendations of any other maintenance items I should should consider at 183k miles, let me know. Besides spark plugs and ignition coils, since I just got those done. TIA!
     
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  7. rjparker

    rjparker Senior Member

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    If it is not a vin number higher than this list you should consider new rings as well. Compare last six digits.

    Excessive Oil Consumption Years Vin.jpg
     
    #7 rjparker, Dec 28, 2021
    Last edited: Dec 28, 2021
  8. Shenine

    Shenine New Member

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    My last 6 are 363303. So that means this does NOT apply to me, right?
     
  9. rjparker

    rjparker Senior Member

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    The production change upgrade started at 791355 so yours is the earlier less desirable design.
     
  10. Shenine

    Shenine New Member

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    oof. What does this mean for me? A trip to the dealer?
     
  11. rjparker

    rjparker Senior Member

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    No help from dealer after 5 years 60k miles. Could have mechanic quote new pistons and rings especially if your head gasket job escalates to a replacement used engine. Main benefit is it eliminates oil consumption and excessive carbon buildup. Some of us believe it’s the root cause of head gasket issues by clogging up everything.
     
  12. Shenine

    Shenine New Member

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    I'll mention it to the mechanic. Any other tsb's I should consider to avoid another engine issue?
     
  13. rjparker

    rjparker Senior Member

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    Make sure the inverter software update is installed. That is a dealer responsibility but they do not automatically do it.

    If there are oil leaks at the timing chain cover, the head gasket repair should fix it. Some mechanics don't follow directions and end up with a leak again.

    After getting your engine fixed, change oil every 5k miles or less. Even if Toyota says 10k miles is ok. Most agree that the 10k interval aggravated excessive oil consumption in these engines along with the design flaw in the piston rings.
     
  14. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Regarding the piston oil ring replacement: that is a BIG, separate job, requires complete engine removal, much additional labour expense. I would not dive into it, just because you're there.

    And, as noted in the Technical Service Bulletin, you would want to have run-away oil consumption, to justify this. The criteria is a quart consumption, every 1100~1300 miles. The attachments show both the test and the ring replacement procedure.

    If you for example are consuming only a pint or so between oil changes, that's not unusual for a higher mileage engine, really doesn't warrant intervention.

    To check your oil consumption, the distance between the two dipstick marks represents 1.6 US quarts (1.5 litres). The marks are spaced roughly 1.5" apart, so each 1/2" is equiv. to 1 pint, aka 2 cups, aka 1/2 quart (roughly 0.5 litre). Attached is an excerpt from Owner's Manual, showing how to read the dipstick. Also attached are the two TS-B's relating to the oil consumption test and the remedy.

    If I was in a high oil consumption situationa, and was going to undertake the oil ring change, I might just replace with the old styly rings, simply because it's less involved. Changing just the rings means you don't need to also change the pistons. This in itself is a saving in parts of maybe $200 USD, or more. Secondly, it's a lot simpler; the pistons don't need to be disassembled, just cleaned up. The old-style rings may be more problematic, but they're not bad, and should be good for at least another 100~150K miles.
     

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  15. Shenine

    Shenine New Member

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    Alrighties, so I got my car back on the 11th. So far, I have noticed the engine sounds stronger and my mpg is much better. But, I do notice I can still feel and hear when the ICE kicks in; not every time, but enough for me to question. I can only best describe it as a jolt, or a bit of a rumble in; and not sure if its my anxiety, but like a much more rapid and less intense version of the shakes pre-gasket repair. Does that make sense? If anything I can try to make a video.

    I suppose I’m asking what engine sounds and feelings are normal given my car’s age and circumstances. Should I “feel” when the ICE kicks in while driving? I’m also finding when I accelerate, the car almost feels like its rejecting it and you can feel the vibration in the cabin. Someone else posted about this today as well post-gasket.
     
  16. Shenine

    Shenine New Member

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    @Mendel Leisk I would love your opinion on this, if you get a chance.
     
  17. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Yeah not sure what to say; I'm by no means a mechanic, just piecing together info like lots here. You get the sense something feels different, could be a "slightly" bent piston arm, or maybe the damper between engine and transaxle?
     
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  18. vvillovv

    vvillovv Senior Member

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    This happened with the Prime when it was new too. Not all owners agreed that the switchover was an issue, but it was reported by several owners when there Primes were new, including me.
    Things that made it worse for me were asking for heavy torque. Uphill climbs and especially in colder weather.
    Much less noticeable when the ICE fired going downhill and at slower speeds as long as it wasn't uphill.
    Hypermiling techniques like backing off the Go Pedal helped too. But is really hard backing off the Go Pedal while mounting a hill in traffic or on the highway.
    Anything you can think of to reduce the shakes when they happen should make some difference in both the cars responsiveness and your sensitivity to the issue.
     
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  19. Shenine

    Shenine New Member

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    I have an update y'all: today I drove around and did some errands, paying attention to the sounds and vibrations of the car. To my surprise, everything was extremely smooth and I could barley tell when the ICE kicked in. This is by far the smoothest my car has ever driven since I have owned it. Maybe it was "adjusting to the new gasket? Who knows.

    @Mendel Leisk @vvillovv thank y'all for your responses! I'll update if anything else comes up.
     
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  20. vvillovv

    vvillovv Senior Member

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    Good news! Don't forget about the EGR valve pipe and ducts that were cleaned. Since a buggered EGR system is thought to be the precursor to many head gasket issues. That's a lot of new data for the computers to adjust for.
     
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